William ate 4 slices of pizza. Omar ate 1 slice. If there were initially 7 slices, what fraction of the pizza is remaining?
$\text{fraction of pizza eaten} = \dfrac{\text{number of slices remaining}}{\text{number of slices total}}$ Together they ate 5 slices, which leaves 2 out of 7 slices remaining. There is $\dfrac{2}{7}$ of the pizza remaining.